Nano-technology for Real-Time Control of the Red Palm …
329
• “A wireless communication interface, able to deliver data messages reporting the
results of RPW activity” (http://www.mdpi.com/1424-8220/13/2/1706/htm).
The audio probe provides the signal captured from the palm tree with the highest possible quality. The weight and size of the sensor must be small enough to be
installed on the palm tree. Concerning the audio acquisition task, there are two possible ways: First option uses four-wire audio interface. The use of an external audio
Coder/Decoder (CODEC) is mandatory. Some CODECs include an amplification
stage, which may be an advantage. The second option uses the Analog-to-Digital
Converter (ADC). The audio implementation should be done using the on-chip ADC
of the microcontroller to digitalize the audio. The advantage of this option is that
the parameters and power consumption of the amplification stage may be fine-grain
designed, so we have decided to use this approach in our sensor. Regarding the power
supply, the sensor measured consumption rises up to 200 mA when performing the
detection process. Four stages for RPW detection are identified: sound acquisition,
digitalization, audio analysis, and transmission of results. Finally, the radio interface
is up to create a reliable point-to-point outdoor communication over distances of
30 m. The 30 m maximum reliable range has been proposed after performing some
experimental field tests with two sensor prototypes.
The audio probe is composed of three elements: the microphone, the probe and
the signal conditioning stage. A wireless microphone contains a radio transmitter. It
transmits the audio as a radio rather than via a cable. It sends its signal using a small
FM radio transmitter to a nearby receiver connected to the sound system. To assign
the sound sensor to the palm tree, two distinctive probe designs were considered. The
first comprises of appending the sensor to the palm tree surface. The fundamental
benefit of this approach is the low or even invalid effect on the palm tree structure.
A 1 cm diameter circle has been sanded down to accommodate the sensor, which
is held with a strap around the palm tree. Experiments have demonstrated that it is
very difficult to settle the sensor close to the stem. Likewise, this appending strategy
leaves the sensor visible to environmental noise, which in urban zones and parks may
be higher than sounds originating from the palm tree trunk. The second option was
to utilize a nail to embed the sensing or detecting device inside the palm tree. This
alternative gives two focal points: The sensor is nearer to the sound source and it is
confined from outside noise. The fundamental disservice is the damage caused to the
palm tree, leaving a 1 cm diameter hole. It requires being amazingly cautious when
removing the probe, filling the influenced area with proper putty material and/or
painting it with a fungicide. An aluminium probe was used because it is resistant to
corrosion and easy to work, with a 10 mm of interior diameter, and around 10 cm
of length to get the maximum sound transmission and to avoid an excessive injury
to the palm tree. Finally, the microphone has been situated on the outer side of the
probe to get a better sound transmission, leaving the other end opened.
Once the audio sensor and the probe have defined (Fig. 4), some signal conditioning was performed to deliver the microphone output signal to the A/D converter
with the highest possible quality (amplification stage). A printed circuit board (PCB)
has been planned, where two of the operational enhancers are utilized to amplify the
329
• “A wireless communication interface, able to deliver data messages reporting the
results of RPW activity” (http://www.mdpi.com/1424-8220/13/2/1706/htm).
The audio probe provides the signal captured from the palm tree with the highest possible quality. The weight and size of the sensor must be small enough to be
installed on the palm tree. Concerning the audio acquisition task, there are two possible ways: First option uses four-wire audio interface. The use of an external audio
Coder/Decoder (CODEC) is mandatory. Some CODECs include an amplification
stage, which may be an advantage. The second option uses the Analog-to-Digital
Converter (ADC). The audio implementation should be done using the on-chip ADC
of the microcontroller to digitalize the audio. The advantage of this option is that
the parameters and power consumption of the amplification stage may be fine-grain
designed, so we have decided to use this approach in our sensor. Regarding the power
supply, the sensor measured consumption rises up to 200 mA when performing the
detection process. Four stages for RPW detection are identified: sound acquisition,
digitalization, audio analysis, and transmission of results. Finally, the radio interface
is up to create a reliable point-to-point outdoor communication over distances of
30 m. The 30 m maximum reliable range has been proposed after performing some
experimental field tests with two sensor prototypes.
The audio probe is composed of three elements: the microphone, the probe and
the signal conditioning stage. A wireless microphone contains a radio transmitter. It
transmits the audio as a radio rather than via a cable. It sends its signal using a small
FM radio transmitter to a nearby receiver connected to the sound system. To assign
the sound sensor to the palm tree, two distinctive probe designs were considered. The
first comprises of appending the sensor to the palm tree surface. The fundamental
benefit of this approach is the low or even invalid effect on the palm tree structure.
A 1 cm diameter circle has been sanded down to accommodate the sensor, which
is held with a strap around the palm tree. Experiments have demonstrated that it is
very difficult to settle the sensor close to the stem. Likewise, this appending strategy
leaves the sensor visible to environmental noise, which in urban zones and parks may
be higher than sounds originating from the palm tree trunk. The second option was
to utilize a nail to embed the sensing or detecting device inside the palm tree. This
alternative gives two focal points: The sensor is nearer to the sound source and it is
confined from outside noise. The fundamental disservice is the damage caused to the
palm tree, leaving a 1 cm diameter hole. It requires being amazingly cautious when
removing the probe, filling the influenced area with proper putty material and/or
painting it with a fungicide. An aluminium probe was used because it is resistant to
corrosion and easy to work, with a 10 mm of interior diameter, and around 10 cm
of length to get the maximum sound transmission and to avoid an excessive injury
to the palm tree. Finally, the microphone has been situated on the outer side of the
probe to get a better sound transmission, leaving the other end opened.
Once the audio sensor and the probe have defined (Fig. 4), some signal conditioning was performed to deliver the microphone output signal to the A/D converter
with the highest possible quality (amplification stage). A printed circuit board (PCB)
has been planned, where two of the operational enhancers are utilized to amplify the